A resin multilayer substrate includes a multilayer body including resin base-material layers in a thickness direction, a side-surface conductor on at least a side surface of the multilayer body and made of a metallic material with a coefficient of thermal expansion whose difference from a coefficient of thermal expansion of the resin base-material layers in a plane direction is smaller than a difference from a coefficient of thermal expansion of the resin base-material layers in the thickness direction, a circuit component in the multilayer body and defining a circuit, and inner conductors in the multilayer body, located between the side-surface conductor and the circuit component along the side-surface conductor, and at least partially overlapping each other when viewed in the thickness direction, each of the inner conductors being one of a dummy conductor and a ground conductor.

A multilayer circuit board includes a resin body, signal wires, ground conductors, and a via conductor. The resin body includes resin layers made from thermoplastic resin. The signal wires and the ground conductors are each on or inside the resin body. The via conductor connects corresponding ones of the signal wires to each other or corresponding ones of the ground conductors to each other. The ground conductors include a counter ground conductor on or inside the resin body, facing a signal wire in a stacking direction in which the resin layers are stacked, and overlapping the signal wire in plan view in the stacking direction. The counter ground conductor is made of a graphite sheet including main surfaces and end surfaces covered with a conductor layer. The graphite sheet extends over rigid and flexible portions in plan view in the stacking direction.

A multilayer substrate includes a resin multilayer body including, in a lamination direction, first and second laminate portions respectively including first and second thermoplastic resin layers, and a first interlayer connection conductor extending through the first thermoplastic resin layer. A storage elastic modulus of the first thermoplastic resin layer is lower than that of the second thermoplastic resin layer at a measurement temperature equal to or higher than a minimum melting point among melting points of metallic elements included in the first interlayer connection conductors and equal to or lower than melting points of the first thermoplastic resin layer and the second thermoplastic resin layer.

A method is for making an electronic device that includes a multilayer circuit board having a non-planar three-dimensional shape defining a membrane switch recess therein. The multilayer circuit board may include at least one liquid crystal polymer (LCP) layer, and at least one electrically conductive pattern layer thereon defining at least one membrane switch electrode adjacent the membrane switch recess to define a membrane switch. The electronic may further include a compressible dielectric material filling the membrane switch recess. The electronic device may also include at least one spring member within the membrane switch recess.

One exemplary aspect relates to a process and apparatus for selectively changing adhesion strength between a flexible substrate and a carrier at specific locations to facilitate shipping and subsequent removal of the flexible substrate from the carrier. The process includes providing a flexible substrate comprising a plurality of integrated circuits thereon providing a carrier for the flexible substrate and adhering the flexible substrate to the carrier by creating an interface between the flexible substrate and the carrier. The process further includes changing the adhesion force between the flexible substrate and the carrier at selected locations by non-uniform treatment of the interface between the flexible substrate and the carrier with an electromagnetic radiation source (e.g. a laser, flashlamp, high powered LED, an infrared radiation source or the like) so as to decrease or increase the adhesion force between a portion of the flexible substrate and the carrier at the selected location.

In a built-in coil substrate, coil conductor patterns are provided on insulating base materials. Coil interlayer connection conductors, which provide interlayer connection between the coil conductor patterns, are provided on the insulating base materials and made of conductive paste. First and second external electrodes are provided on a first principal surface of a multilayer body. One of the coil conductor patterns is connected to the first external electrode by first-external-electrode connection conductors made of the conductive paste. Another one of the coil conductor patterns is connected to the second external electrode by a second-external-electrode connection conductor. The second-external-electrode connection conductor is a metal film provided in a through hole that extends through the multilayer body in a stacking direction in which the insulating base materials are stacked.

A method for manufacturing a circuit board, includes obtaining a second laminated body by laminating, in this order, an uncured second insulating substrate and a resin film on a second surface opposite to a first surface of a cured first insulating substrate of a first laminated body, and performing thermocompression bonding thereon. The first laminated body includes the first insulating substrate and a metal layer that is formed into a pattern shape on the first surface of the first insulating substrate. A third laminated body is obtained by forming a hole that reaches the metal layer, in the resin film, the second insulating substrate, and the first insulating substrate, from a resin film side of the second laminated body, filling conductive paste into the hole, and then peeling off the resin film. Thermocompression bonding is performed by stacking one third laminated body and another third laminated body.

An ESD protection device includes a first terminal and a second terminal defining a first balanced port, a third terminal and a fourth terminal defining a second balanced port, and a ground terminal. A first coil and a third coil are provided between the first terminal and the third terminal to cancel an inductance component of a first ESD protection circuit. A second coil and a fourth coil are provided between the second terminal and the fourth terminal to cancel an inductance component of a second ESD protection circuit.

A resin substrate includes an insulating substrate, and first and second signal conductors that partially extend in parallel or substantially in parallel with each other along a signal transmission direction. The first signal conductor includes a parallel portion that extends in parallel or substantially in parallel with the second signal conductor along the signal transmission direction, and a first connection portion. In a portion where the first signal conductor and the second signal conductor extend in parallel or substantially in parallel with each other, the first signal conductor and the second signal conductor are disposed at a same position in the thickness direction of the insulating substrate, and the first connection portion is disposed at a different position from the second signal conductor in the thickness direction and a width direction of the insulating substrate.

A multilayer resin substrate includes resin substrates laminated together, an overlapping portion in which a signal line as a conductor pattern and another conductor pattern overlap each other in a laminating direction of the resin substrates, and a non-overlapping portion in which the signal line and the other conductor pattern do no overlap each other in the laminating direction. A thin portion is provided at a position in the non-overlapping portion near the overlapping portion. The thin portion is a portion of the multilayer resin substrate which has a thickness smaller than the thickness in the overlapping portion in the laminating direction of the resin substrates.